I'm a big fan of the personalized tags (i.e. #stuff.mk), but I think the implementation could be just a little bit better. Right now, if I want people to be able to follow all of my #linux posts, I have to tag posts as both #linux and #linux.doesntgolf, and people would have to follow #linux.doesntgolf. I think it'd make a lot more sense if I just tag everything as I normally would (without the personalized stuff), and someone that wants to follow all of my #music posts but not all #music posts can just follow #music.doesntgolf (or whatever other format might be put in place).